1. Field of the Invention
The present invention relates to resonators for an apparatus for bonding members together with ultrasonic vibration.
2. Description of the Prior Art
Japanese Patent Application Kokai No. 54-13349 discloses an ultrasonic vibration bonding machine for bonding workpieces held between a mount and a resonator which is connected to a transducer.
The resonator comprises an ultrasonic horn made from aluminum, iron, or titanium. A primary product is machined to a shape and size which are determined by the material, thickness, and shape of the members to be bonded and an oscillation output of the transducer. The primary product is then connected to the transducer for vibration. In order to provide the desired resonance, the primary product is subjected to secondary processing to adjust the length and thickness of the primary product for fine tuning. When the bonding working portion of the ultrasonic horn is brought into contact with the overlapped workpieces and an ultrasonic wave is supplied, the bonding working portion is worn down by diffusion caused by bonding temperatures. If the surface of the bonding working portion becomes rough by repetition of such abrasion or diffusion, a bonding failure of the workpieces can take place or a bonding flaw can be made on the surface of a workpiece, resulting in the poor quality and low reliability. Therefore, it is necessary to polish the surface of the bonding working portion for repair. However, the ultrasonic horn must be removed from the resonator to repair the bonding working portion. The assembly and tuning of the resonator require a considerable amount of time and labor. In addition, the polishing margin of the bonding working portion is so small to provide an appropriate resonance that the bonding working portion cannot be used after several times of repair, and the old ultrasonic horn must be replaced with a new one. Since the ultrasonic horn must be replaced with a new one when the bonding working portion is worn out, such a resonator is very uneconomical for the user. The ultrasonic horn is made by precision machining, the unit cost thereof is very high.